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I am confused, can evolution ( speciation ) really occur in such a short time? Well, Evolution and Speciation are not the same. Evolution is the adaptation of an existing species to an environment over generations. Speciation is the development of a new species, and the definition of "species" can vary depending on who you talk to - but a very commonly ...

Evolution can occur in just one full generation Strong selection will rapidly reduce the gene frequencies of genes which cause negatively selected phenotypes. This reduces the likelihood of unfavourable genotypes occurring in the next generation. (I regard generation here as the complete cycle of one individual being born to the point at which they ...

Well, what you seem to be suggesting is "Did life evolve twice on Earth?" Your original question has an answer: Probably yes. It's not unlikely to think that the original cell evolved into two different paths and then one went extinct. However, that doesn't address LUCA. If we found fossil evidence of what we thought was LUCA, and then fossil evidence that ...

How are such species are defined, and at what point dogs stop being dogs anymore? This is a bit like the is-Pluto-a-planet-discussion. A group of scientists have to come together and hold a big conference. You have a few principles that you want to adhere to and then it's big groups of people making decisions.

There are many definitions of a species, which may or may not include the concept of reproductive barrier. The Biological Species Concept (BSC) is quite popular and involves a reproductive barrier, but other concepts such as the Phylogenetic Species Concept do not include a reproductive barrier. Disagreements and confusion also happen over just what the ...

By definition, polyploidy just means that a cell or organism contains more than 2 pairs of homologous chromosomes (or is more than 2n). This is more common in plants than it is in animals. The plant, as shown below, undergoes failed meiosis, which means that the diploid (2n) cells never become haploid (n). As a result, a plant ends up with more than 2n when ...

I've never heard of it, actually - though I can't speak for my professors or researchers I know, none have ever presented the Cladism argument as an argument for the delineation of species. As far as I'm aware, the attempts to define a species fall along three lines: The ability to produce fertile offspring in the wild. Distinct physical characteristics. ...